Hernandez was known as Angel Heredia when he admitted to a San Francisco court in May 2008 that he had supplied Olympians, including Marion Jones and Tim Montgomery, with performance enhancing substances.

In a conference call with RingTV and other boxing media, Marquez defended Hernandez and said he has no knowledge of his new nutritionist's dealings with steroids.

"I didn't find out any of this other stuff until it was written over the last couple of days. It was big news to me," Marquez said.

"I just knew that he had trained a lot of elite and world class athletes before I met him. We talked about what we needed to do. I was very happy with what he told me that I needed to do," Marquez said, adding that Hernandez has been "a very professional guy."

Take the test?

Marquez says he is willing to undergo any kind of tests to prove that he does not use any kind of performance-enhancing drug.

"If they want to do whatever doping or drug testing they want to do, Olympic-style, or whatever they want to do, I'll do it. I'm prepared," he said.

But Marquez added, "Just as long as (Manny) Pacquiao does it too."

Marquez will face rival Pacquiao for the third time on November 12 at the MGM Grand in Las Vegas.

Preparing for the fight

The Mexican fighter expressed disappointment that all his hard work and preparation for the fight are now being called into question because of the revelations regarding Hernandez.

"All the work that I've done, and how hard that I've worked and all of the preparation, right now, that's being just thrown into the trash can by guys like (Victor) Conte and (Alex) Ariza who are saying these things," Marquez said.

He said he is happy with the training he has gotten from Hernandez and believes he is ready for his bout against Pacquiao.

"I'm very happy with the results. I think it's going to make me a better fighter, and I'm going to be well-prepared when I fight this third fight with Pacquiao," Marquez said.

Legal action?

Victor Conte is the nutritionist of world bantamweight champion Nonito "The Filipino Flash" Donaire Jr., who has also served prison time for providing athletes with steroids through his controversial BALCO laboratory.

Conte had announced through Twitter that Hernandez is the same Heredia who is an 'admitted steroid dealer.'

Ariza, meanwhile, is the strength and conditioning coach of Marquez' November 12 opponent, Pacquiao. He has made some comments regarding Marquez increase in size, saying, "Marquez put on a lot of size really quick... I don't know why Marquez got so big so fast."

"Conte can speak to whatever he wants," Marquez said. "It's his opinion, it's not a fact."

Marquez says he may be considering legal action against Conte if the latter is unable to present facts or proof of his allegations.

"I'm sure that Hernandez is going to be talking to his lawyers and trying to find out why they are saying these things about him, when they have no facts or no evidence to say these things," he said.

Marquez' head coach, boxing Hall-of-Famer Ignacio "Nacho" Beristain, said that he respects Hernandez' work with his boxer.

"(Hernandez) is giving me a guy that I know that I can work with, who is going to be ready," Beristain said. "I just have the utmost respect for what he's done, and how Juan Manuel has responded to his work."